This invention relates to the technical field of a light-sensitive material transporting device which is to be used in an image recording apparatus that exposes light-sensitive materials to form a latent image.
Heretofore, the image recorded on photographic films such as negatives and reversals (which are hereunder referred to simply as "films") has been commonly printed on light-sensitive materials such as photographic paper by means of direct (analog) exposure, in which projected light from the film is allowed to be incident on the light-sensitive material to achieve its areal exposure.
A new technology has recently been introduced and this is a printer that relies upon digital exposure. Briefly, the image recorded on a film is read photoelectrically, converted to a digital signal and subjected to various image processing operations to produce image data for recording purposes; recording light that has been modulated in accordance with the image data is used to scan and expose a light-sensitive material to record a latent image, which is subsequently developed and output as a print (photograph). The printer operating on this principle has been commercialized as a digital photoprinter.
In the digital photoprinter, the image on a film is read photoelectrically and gradation correction and other operations are performed by subsequent image (signal) processing to determine exposing conditions. Hence, the digital photoprinter has many capabilities in image processing such as editing of printed images by, for example, assembling a plurality of images or splitting a single image into plural images, as well as color/density adjustment and edge enhancement; as a result, prints can be output as needed by specific uses. In addition, the data on a printed image can be supplied into a computer or the like and stored in recording media such as a floppy disk or a hard disk.
A further advantage of the digital photoprinter is that compared to the prints produced by the conventional method of direct exposure, those which are output by the digital photoprinter have better image quality in such aspects as resolution and color/density reproduction.
Having these features, the digital photoprinter is basically composed of an input machine having a scanner (image reader) and an image processor and an output machine having both an exposing device (image recording device) and a developing device.
In the scanner, projected light carrying the image recorded on a film is read photoelectrically with an image sensor such as a CCD sensor and the captured image is sent to the image processor as data for the image on the film (i.e., the image data signal). In the image processor, the image data from the scanner are subjected to specified image processing operations and the resulting output image data for image recording (i.e., exposing conditions) are sent to the exposing device.
In the exposing device, if it is of a type that relies upon exposure by scanning with an optical beam, the latter is modulated in accordance with the received image data and deflected in a main scanning direction as the light-sensitive material is transported in an auxiliary scanning direction perpendicular to the main scanning direction, whereby a latent image is formed as the result of scan exposure of the light-sensitive material with the optical beam and a back print is also recorded. In the developing device, the exposed light-sensitive material is subjected to development and other specified processing operations so as to output a print which reproduces the image that has been recorded on the film.
In the exposing device, whether it is in the digital photoprinter or an ordinary photoprinter that relies upon "direct" exposure, a virgin light-sensitive material is in the form of a magazine, i.e., a roll contained in a lightproof case. The light-sensitive material is withdrawn out of the magazine in the exposing device and further transported for exposure and other necessary steps.
In the ordinary photoprinter, the light-sensitive material being transported is not cut but remains a web as it is subjected to exposure, back print recording, development, rinse, drying and other necessary steps and only after these steps are complete, the light-sensitive material is cut to individual prints of a specified length.
This process requires that frame information (frame punches) for delineating individual frames (or prints) be formed before or during the exposure of the light-sensitive material. However, the portion of the light-sensitive material where the frame information is formed is simply a waste of space. In addition, frame information have to be formed by special means having a punch, a sensor or the like.
In the exposing device of a digital exposure type, the light-sensitive material must be transported for scanning in high precision and without stops in order to record images of high quality that are free from unevenness and other defects. In order to meet this need, the exposing device in the digital photoprinter is adapted to make a slack (loop) out of the light-sensitive material both upstream and downstream of the exposing position but this only increases the complexity of the transport zone for the light-sensitive material and the mechanism for its control.
Under the circumstances, an exposing device is desired that can be incorporated in a digital photoprinter and which is capable of exposing a light-sensitive material after it is cut to sheets corresponding to individual prints to be finally produced. In fact, this need has been satisfied commercially with an analog photoprinter.
In order to produce prints with high efficiency, cut sheets of the light-sensitive material have to be transported smoothly (without jamming or other troubles) over specified paths so that they can be subjected to back printing, exposure and other operations efficiently before they are supplied to the developing machine. However, the cut sheets of the light-sensitive material have "curls" or retain the curvature imparted when the light-sensitive material was in a roll form and jamming is sure to develop unless it is retained positively during transport.
Another factor that must be considered with photoprinters is that development and subsequent steps generally take more time than exposure. Under the circumstances, an apparatus of the type that performs exposure on the cut sheets of the light-sensitive material is adapted to be such that a distributing section is provided between the exposing section and the site at which the light-sensitive material is supplied to the developing machine (this step may be called "entry into the processor"). The cut sheets of the light-sensitive material, before they are fed into the developing machine, are distributed in a direction perpendicular to the direction of their transport so as to form a plurality of rows that overlap in the transport direction. In this way, the throughput of the developing machine can be improved over the case where individual sheets of the light-sensitive material are processed in a single row (almost doubled in two rows and tripled in three rows) and the difference in speed between exposure and development processing is practically cancelled.
If jamming or other troubles occur in this distributing section, the light-sensitive material is adversely affected either during exposure or in the midst of its entry into the developing machine and only inappropriate prints will be produced.
What is more, distribution of the cut sheets of the light-sensitive material should not affect its exposure and entry into the processor. In order to meet this requirement, the conventional distributing section is adapted to consist of three blocks, a high-speed transport block, a distributing block and a speed regulating block; in the high-speed transport block, the sheets of light-sensitive material emerging from the exposing section are transported into the distributing block at high speed so that the distance to the next coming sheet is long enough to secure the time necessary for performing the intended distribution and in the distributing block, the sheets are distributed sidewise by a suitable method such as moving the sheets sidewise together with the transport means and thereafter transported into the speed regulating block, where the transport speed of the sheets is adjusted to one that is compatible with development before they are fed into the developing machine. As the result, the pathlength of the light-sensitive material in the distributing section increased considerably and the size and cost of the photoprinter will increase accordingly.